"Karmanyevadhikaraste ma phaleshu kadachana, Ma karma phala hetur bhurmatey sangostva akarmani."

Interview questions

Manual test cases for file uploading:
When upload file upload button must be disable until file
is selected.
check for the Upload button whether it opens a my documents dialogue box to select a file
check for the blank file, files without any content
should not be uploaded-should get error message
Check image upload with image size greater than the max allowed size. Proper error message should be displayed
Check to get error message when unsupported file type is uploaded
Check Once uploaded the file name shows next to it
how much time it will take to upload the same size of file
Image upload progress bar should appear for large size images
Check if cancel button functionality is working in between upload process
Check multiple file upload functionality
Check image quality after upload. Image quality should not be changed after upload

Write a program to find the length of the string and print only the alphabetical characters out of it. String was "A:B:C:D"

public String getStringOfLettersOnly(String s) {
    //using a StringBuilder instead of concatenate Strings
    StringBuilder sb = new StringBuilder();
    for(int i = 0; i < s.length(); i++) {
        if (Character.isLetter(s.charAt(i))) {
            //adding data into the StringBuilder
            sb.append(s.charAt(i));        }    }
    //return the String contained in the StringBuilder
    return sb.toString();}
Write a SQL query to write the date in a given format.

SELECT DATE_FORMAT('1997-10-04 22:23:00', '%W %M %Y');
+---------------------------------------------------------+
| DATE_FORMAT('1997-10-04 22:23:00', '%W %M %Y')          |
+---------------------------------------------------------+
| Saturday October 1997

Have you used String, StringBuffer, StringBuilder classes in Java. Is String class mutable or immutable?
String class is mutable
The StringBuffer and StringBuilder classes are used when there is a necessity to make a lot of modifications to Strings of characters.
Unlike Strings objects of type StringBuffer and Stringbuilder can be modified over and over again with out leaving behind a lot of new unused objects. each method in StringBuffer is synchronized that is StringBuffer is thread safe
      String                    StringBuffer         StringBuilder
----------------------------------------------------------------------------------                 
Storage Area | Constant String Pool           Heap                       Heap 
Modifiable     |  No (immutable)            Yes( mutable )          Yes( mutable )
Thread Safe   |           Yes                                  Yes                              No
 Performance |         Fast                                Very slow                    Fast

 Agile:
Product manager, scrum master and team
Product Back logs or epics make into small product backlogs or user stories based on their priorties
Estmate the product back log in points, decide sprint duration,sprint planning, estimate the hours of work, devide the req to tasks, sprint meetings, daily defect track meetings, post its, what work done, any dependencies, what u r working on …track down the progress using burndown chart

based on what features to go divided to release back logs- again make into sprints based on time and priorities
each sprint, last 2 to 4 weeks,   product owner, scrum master,
monitor the progress using burn down charts, based on velocity of chart will determine the release dates
in each sprint will find bugs and fix and by end of sprint, a complete feature will be released


What is Regular expression. Also asked me to write the regular expression for some date
special sequence of characters that helps you match or find other strings or sets of strings, using a specialized syntax held in a pattern.
Date: (1[012]|[19]):[0 5][09 ](am|pm)
(   start with
[ 012]  after 1 it can start with 10 or 11 or 12
|  or
[19] can start with 1 to 9
Am or pm..
(//s) add space

Program to implement a LinkList:

import java.util.*;
 
public class LinkedListDemo {
 
   public static void main(String args[]) {
      // create a linked list
      LinkedList ll = new LinkedList();
      // add elements to the linked list
      ll.add("F");
      ll.add("B");
      ll.add("D");
      ll.add("E");
      ll.add("C");
      ll.addLast("Z");
      ll.addFirst("A");
      ll.add(1, "A2");
      System.out.println("Original contents of ll: " + ll);
 
      // remove elements from the linked list
      ll.remove("F");
      ll.remove(2);
      System.out.println("Contents of ll after deletion: "
       + ll);
      
      // remove first and last elements
      ll.removeFirst();
      ll.removeLast();
      System.out.println("ll after deleting first and last: "
       + ll);

Program to open a file and write or read something in file using java:
import java.io.*;
 
public class FileRead{
 
   public static void main(String args[])throws IOException{
 
      File file = new File("Hello1.txt");
      // creates the file
      file.createNewFile();
      // creates a FileWriter Object
      FileWriter writer = new FileWriter(file); 
      // Writes the content to the file
      writer.write("This\n is\n an\n example\n"); 
      writer.flush();
      writer.close();
 
      //Creates a FileReader Object
      FileReader fr = new FileReader(file); 
      char [] a = new char[50];
      fr.read(a); // reads the content to the array
      for(char c : a)
          System.out.print(c); //prints the characters one by one
      fr.close();
   }
}

Reading from a file plain text:
import java.io.*;
public class Test {
    public static void main(String [] args) {
        String fileName = "temp.txt";
        String line = null;
        try {
            // FileReader reads text files in the default encoding.
            FileReader fileReader =
                new FileReader(fileName);
            BufferedReader bufferedReader =
                new BufferedReader(fileReader);
            while((line = bufferedReader.readLine()) != null) {
                System.out.println(line);
            }  

            bufferedReader.close();                                        
        }
        catch(FileNotFoundException ex) {
            System.out.println(
                "Unable to open file '" +
                fileName + "'");                                             }
        catch(IOException ex) {
            System.out.println(
                "Error reading file '"
                + fileName + "'");          
          ex.printStackTrace();
        }  }}
In order to read from binary files use
  FileInputStream inputStream = 
                new FileInputStream(fileName);
while((nRead = inputStream.read(buffer)) != -1) {
System.out.println(new String(buffer));
                total += nRead;
Writing to File:
import java.io.*;
 
public class Test {
    public static void main(String [] args) {
 
        // The name of the file to open.
        String fileName = "temp.txt";
 
        try {
            // Assume default encoding.
            FileWriter fileWriter =
                new FileWriter(fileName);
 
            // Always wrap FileWriter in BufferedWriter.
            BufferedWriter bufferedWriter =
                new BufferedWriter(fileWriter);
 
            // Note that write() does not automatically
            // append a newline character.
            bufferedWriter.write("Hello there,");
            bufferedWriter.write(" here is some text.");
            bufferedWriter.newLine();
            bufferedWriter.write("We are writing");
            bufferedWriter.write(" the text to the file.");
 
            // Always close files.
            bufferedWriter.close();
        }
        catch(IOException ex) {
            System.out.println(
                "Error writing to file '"
                + fileName + "'");
            // Or we could just do this:
            // ex.printStackTrace();
        }
    }
}
To write binary files to java
FileOutputStream outputStream =
                new FileOutputStream(fileName);
outputStream.write(buffer);
Hash map:
The HashMap class uses a hashtable to implement the Map interface. This allows the execution time of basic operations, such as get( ) and put( ), to remain constant even for large sets.
The HashMap class supports four constructors
It has a number of "buckets" which it uses to store key-value pairs in. this is very efficient for looking up key-value pairs in a map
HashMap works on the principle of hashing
put(key, value): HashMap stores both key and value object as Map.Entry. Hashmap applies hashcode(key) to get the bucket. if there is collision ,HashMap uses LinkedList to store object.
get(key): HashMap uses Key Object's hashcode to find out bucket location and then call keys.equals() method to identify correct node in LinkedList and return associated value object for that key in Java HashMap

In Java, when the “==” operator is used to compare 2 objects, it checks to see if the objects refer to the same place in memory
String obj1 = new String("xyz");
 
String obj2 = new String("xyz");
 
if(obj1 == obj2)
   System.out.println("obj1==obj2 is TRUE");
else
  System.out.println("obj1==obj2 is FALSE");
 
o/p false
 
String obj1 = new String("xyz");
 
String obj2 = obj1;
 
if(obj1 == obj2)
   System.out.println("obj1==obj2 is TRUE");
else
  System.out.println("obj1==obj2 is FALSE");
 
o/p true
String obj1 = new String("xyz");
 
String obj2 = new String("xyz");
 
if(obj1.equals(obj2))
   System.out.printlln("obj1==obj2 is TRUE");
else
  System.out.println("obj1==obj2 is FALSE");
 
Output true
Design pattern: Design patterns are useful because they provide a pre-formulated solution to problems based on the experience of other programmers. This can save you a lot of time.
how to solve a problem in different situations.
Singleton pattern is one of the design patterns that is utilized for restricting instantiation of a class to one or few specific objects................
Process pattern: Methods, best practices, techniques for developing an Object-Oriented software comprises a process pattern..
Access modifiers in java:
·         Visible to the package. the default. No modifiers are needed.
·         Visible to the class only (private).
·         Visible to the world (public).
·         Visible to the package and all subclasses (protected).
Class and interfaces cannot be private.
Using the private modifier is the main way that an object encapsulates itself and hide data from the outside world.
The main() method of an application has to be public. Otherwise, it could not be called by a Java interpreter (such as java) to run the class.
The protected access modifier cannot be applied to class and interfaces. Methods, fields can be declared protected, however methods and fields in a interface cannot be declared protected.

What is data provider in testNG
TestNG lets you pass parameters directly to your test methods in two different ways:
·         With testng.xml
·         With Data Providers
·         When you need to pass complex parameters use Data Providers
·         A Data Provider is a method annotated with @DataProvider. This annotation has only one string attribute: its name. If the name is not supplied, the Data Provider’s name automatically defaults to the method’s name. A Data Provider returns an array of objects.
Unix commands like list all the file names which have some particular text present in them

$ grep check * -lR  

r for recursive, looking for word ‘check’
look for all files except txt or pdf formats I is for ignore case
ls -I "*.txt" -I "*.pdf" -R


Vending machine test cases:
functional testing

check proper change
check improper change
check proper itrem and improper item
no item is there .
more than available items stuffed in the tray
machine does not have change.?


instability testing
check if vending machine can be inztalled properly with proper connection
check if it is movable.


usability testing
check if vending machine has proper buttons
check if it has 0-9 numbers to select
check if it has coin return
dispenser/provision for hands to fit in  to take the product
buttons are not too rough
check for the height of the operationabilty.


performance

how quickly it drops
test on differnt plugs and power 110 v 220 v 440v
test on incremental loads of coins and keep selecting
keep inserting coins continously for 1 hr then select


Stress

shake the machine
switch on/switch off machine alternatingly and select it.
in severe cold/hot atmosphere does it work.
keep inserting coins continously for 1 hr then select
insert nothing and keep pressing

compatibility

 different coins/dollars
 takes a 1 dollr 5 dollar 100 dollar etc....
 can vending machine work properly outside
 
capability testing
  what can vending machine do other than vending solid items ?keep liquid and solid items
  can it be used just for vending coins?(this is a useful feature for taking quarters!!)

equivalence partioning /boundary value.
valid:  correct amount correct selection of an item
       invalid : no amount -item selection
           no item -amount inserted and verify if the system takes it.

o    Unit testing: I had candidate going really deep in the circuitry of the machine, testing each individual transistors. Most go to a higher level and test each individual functional component.
o    Functional testing: Some candidate approach functional testing through the actual mechanics of the machine (buttons, display etc.) while some other approach it from a software angle, leaving aside the mechanics. The best tester covers both.
o    White box/Black box: Again, your mileage may vary and you really see where your candidate is the most comfortable.
o    Performance/reliability testing: How fast can I get my coffee? How many coffee can I deliver in rush hours, MTBF etc. You can have a lot of fun in this area.
o    Usability: So much to do in the area but most candidate forget about it.
o    Localization testing: Again, most candidate don’t think about this one.
o    Security testing: Most candidate don’t go there but it’s always a good sign if they do. I had candidate forcing the door to get money, throwing water on it to see how far they can go until a power surge, sending 300v in the thing to understand how it would react etc.

If the log file is really big , how to check last few logs of log file  :
Grep test /etc/logfile |  tail  -l

first n lines Syntax: head -n N FILENAME
$ head -n 15 /var/log/maillog
Ignore last 250 lines:$ head -n -250 /var/log/secure
Last n lines: $ tail -n 50 /var/log/messages
To view newer contents: $ tail -f /var/log/syslog
 
 
How to remotely access other linux machine
Configure remote access in the ubantu machine
In windows install vnc programme and add the remote machine address in it
In ubantu install ssh and make the port open 22
In windows install ssh client software i.e putty and enter login pwd and start accessing linux
what is rowid in Oracle database
ROWID is the physical location of a row. Consequently it is the fastest way of locating a row,
It is address of the row..

             what is primary key and unique constrain 
                  A primary key is a unique field on a table but it is special in that the table considers that row its key. That means that other tables can use this field to create foreign key relationships to themselves.
A unique constraint simply means that a particular field must be unique.

What are the prerequisites to run Java code on your local machine:
download java and run the .exe to install Java on your machine
you would need to set environment variables to point to correct installation directories:
·         Right-click on 'My Computer' and select 'Properties'.
·         Click on the 'Environment variables' button under the 'Advanced' tab.
·         Now, alter the 'Path' variable so that it also contains the path to the Java executable. Example, if the path is currently set to 'C:\WINDOWS\SYSTEM32', then change your path to read 'C:\WINDOWS\SYSTEM32;c:\Program Files\java\jdk\bin'.
Write java program in notepad or eclpse…and save as xxx.java
public class MyFirstJavaProgram {
 
   /* This is my first java program.  
    * This will print 'Hello World' as the output
    */
 
    public static void main(String []args) {
       System.out.println("Hello World"); // prints Hello World
    }
}
·         Open a command prompt window and go o the directory where you saved the class. Assume it's C:\.
·         Type ' javac MyFirstJavaProgram.java ' and press enter to compile your code. If there are no errors in your code, the command prompt will take you to the next line (Assumption : The path variable is set).
·         Now, type ' java MyFirstJavaProgram ' to run your program.
·         You will be able to see ' Hello World ' printed on the window.
For all class names the first letter should be in Upper Case. 
·          All method names should start with a Lower Case letter.  Name of the program file should exactly match the class name Examples of legal identifiers: age, $salary, _value, __1_value
·         Examples of illegal identifiers: 123abc, -salary
Java programme:
import java.io.*;
public class Employee{
   String name;
   int age;
   String designation;
   double salary;
         
   // This is the constructor of the class Employee
   public Employee(String name){
      this.name = name;
   }
   // Assign the age of the Employee  to the variable age.
   public void empAge(int empAge){
      age =  empAge;
   }
   /* Assign the designation to the variable designation.*/
   public void empDesignation(String empDesig){
      designation = empDesig;
   }
   /* Assign the salary to the variable     salary.*/
   public void empSalary(double empSalary){
      salary = empSalary;
   }
   /* Print the Employee details */
   public void printEmployee(){
      System.out.println("Name:"+ name );
      System.out.println("Age:" + age );
      System.out.println("Designation:" + designation );
      System.out.println("Salary:" + salary);
   }
}
As mentioned previously in this tutorial, processing starts from the main method. Therefore in-order for us to run this Employee class there should be main method and objects should be created. We will be creating a separate class for these tasks.Save the following code in EmployeeTest.java file
import java.io.*;
public class EmployeeTest{
 
   public static void main(String args[]){
      /* Create two objects using constructor */
      Employee empOne = new Employee("James Smith");
      Employee empTwo = new Employee("Mary Anne");
 
      // Invoking methods for each object created
      empOne.empAge(26);
      empOne.empDesignation("Senior Software Engineer");
      empOne.empSalary(1000);
      empOne.printEmployee();
 
      empTwo.empAge(21);
      empTwo.empDesignation("Software Engineer");
      empTwo.empSalary(500);
      empTwo.printEmployee();
   }
}
Now, compile both the classes and then run EmployeeTest to see the result as follows:
C :> javac Employee.java
C :> vi EmployeeTest.java
C :> javac  EmployeeTest.java
C :> java EmployeeTest
Name:James Smith
Age:26
Designation:Senior Software Engineer
Salary:1000.0
Name:Mary Anne
Age:21
Designation:Software Engineer
Salary:500.0


2) What is the difference in the versioning format in Java (Eg:- 1.5 vs 5.0)
Where there was 1.5.0 now make into 5.0

Thread:All Java programs have at least one thread, known as the main thread, which is created by the JVM at the program’s start, when the main() method is invoked with the main thread. In Java, creating a thread is accomplished by implementing an interface and extending a class. Every Java thread is created and controlled by the java.lang.Thread class.

When a thread is created, it is assigned a priority. The thread with higher priority is executed first, followed by lower-priority threads
Collections:

Sort array of strings:
String [] strs=(“ggg”,”jkj”,”jkjkj”);
Arrays.sort(strs);
Sort chars in string:
// put the characters into an array
Character[] chars = new Character[str.length()];
for (int i = 0; i < chars.length; i++)
    chars[i] = str.charAt(i);
 
// sort the array
Arrays.sort(chars, new Comparator<Character>() {
    public int compare(Character c1, Character c2) {
        int cmp = Character.compare(
            Character.toLowerCase(c1.charValue()),
            Character.toLowerCase(c2.charValue())
        );
        if (cmp != 0) return cmp;
        return Character.compare(c1.charValue(), c2.charValue());
    }
});
 
// rebuild the string
StringBuilder sb = new StringBuilder(chars.length);
for (char c : chars) sb.append(c);
str = sb.toString();

(or)
1.    import java.util.Arrays;
2.     
3.    public class SortStringArrayExample {
4.           
5.            public static void main(String args[]){
6.                   
7.                    //String array
8.                    String[] strNames = new String[]{"John", "alex", "Chris", "williams","Mark", "Bob"};
9.                   
10.                  /*
11.                   * To sort String array in java, use Arrays.sort method.
12.                   * Sort method is a static method.               *
13.                   */
14.                 
15.                  //sort String array using sort method
16.                  Arrays.sort(strNames);
17.                 
18.                  System.out.println("String array sorted (case sensitive)");
19.                 
20.                  //print sorted elements
21.                  for(int i=0; i < strNames.length; i++){
22.                          System.out.println(strNames[i]);
23.                  }
24.                 
25.                  /*
26.                   * Please note that, by default Arrays.sort method sorts the Strings
27.                   * in case sensitive manner.
28.                   *
29.                   * To sort an array of Strings irrespective of case, use
30.                   * Arrays.sort(String[] strArray, String.CASE_INSENSITIVE_ORDER) method instead.
31.                   */
32.                 
33.                  //case insensitive sort
34.                  Arrays.sort(strNames);
35.                 
36.                  System.out.println("String array sorted (case insensitive)");
37.                  //print sorted elements again
38.                  for(int i=0; i < strNames.length; i++){
39.                          System.out.println(strNames[i]);
40.                  }
41.   
42.          }
43.  }

reverse a string:
new StringBuilder(“meeraja”).reverse().toString();
 

String s = "sample";
String result = new StringBuffer(s).reverse().toString();

import java.util.*;
 
class ReverseString
{
   public static void main(String args[])
   {
      String original, reverse = "";
      Scanner in = new Scanner(System.in);
 
      System.out.println("Enter a string to reverse");
      original = in.nextLine();
 
      int length = original.length();
 
      for ( int i = length - 1 ; i >= 0 ; i-- )
         reverse = reverse + original.charAt(i);
 
      System.out.println("Reverse of entered string is: "+reverse);
   }
}